Conventionally, acoustic generators represented by a piezoelectric speaker have been known as pieces of small-sized sound equipment driven with a low electrical current that use a piezoelectric body for an electroacoustic transducer element. For example, the acoustic generators are used as sound generation devices that are incorporated in small-sized electronic devices such as mobile computing apparatuses.
In general, the acoustic generators that use the piezoelectric body for the electroacoustic transducer element has the following configuration. That is, a piezoelectric element on which an electrode formed by a silver thin film or the like is formed is bonded to a vibration plate made of metal with an adhesive. A sound generation mechanism of the acoustic generator using the piezoelectric body for the electroacoustic transducer element generates shape distortion on the piezoelectric element by applying an alternate-current voltage to both the surfaces of the piezoelectric element and transmits the shape distortion of the piezoelectric element to the vibration plate made of metal so as to cause the vibration plate to vibrate.